<span>Repeated and prolonged episodes of stress can cause a state of exhaustion within the immune system which can ultimately cause infection.</span>
There are two important regions of a lipid that provide the structure of the lipid bilayer. Each lipid molecule contains a hydrophilic region, also called a polar head region, and a hydrophobic, or nonpolar tail region
The approach that you're mentioning is called the <span>sociobiology approach. It's basically approaching biology and evolution but also including principles found in sociology.</span>
The number of covalent bond an element can form depends on the number of electrons it has in its outermost shell (valence electrons). Carbon has four valence electrons, therefore, it can form maximum of four covalent bonds in an organic compound.
According to the 2011 Earth Science Reference Table, Selenite Gypsum has an approximate hardness of 2.
The hardness of calcite is 3.
The hardness of apatite is 5 according to the Moh's hardness scale.
The hardness of diamond is 10.
